1. Field of Invention
The present invention relates to an air tool of an air impact driver, an air impact wrench or a power source of a motor driven by compressed air, particularly relates to an air tool which can be connected to a high pressure air compressing apparatus supplying high pressure air.
2. Description of Related Art
Generally, according to an air tool of a nailing machine, an air impact driver, an air duster or the like, two kinds of a low pressure specification constituting a range of use by compressed air in a normal pressure (low pressure) region having an upper limit pressure up to 0.98 MPa and a high pressure specification constituting a range of use by compressed air in a high pressure region of 1 through 2.48 MPa with object of promotion of a function or small-sized and light-weighted formation of an air tool have been reduced into practice. Particularly, a tool of a high pressure specification is fabricated by a structure of capable of ensuring to withstand high pressure air in comparison with a tool of a low pressure specification from a view point of breakage and safety of an apparatus. There is a case in which the two kinds of air tools having different specifications of compressed air are simultaneously used at an operation site of the same construction site or the like.
Therefore, one piece of a high pressure air compressing machine (high pressure air compressor) constituting a drive source of the air tools is generally provided with two pieces of take out ports for taking out compressed air of the high pressure specification and compressed air of the low pressure specification independently from each other by aiming at a reduction in installation cost and promotion of a way of use. However, in this case, when an interchangeability is provided to modes of connecting an air hose including a socket member, a plug member and a hose member of the high pressure air take out port and the low pressure air take out port, for example, there is a concern of connecting an air tool of the low pressure specification to the high pressure air take out port, conversely, connecting an air tool of the high pressure specification to the low pressure air take out port, in the former case, there poses a problem of destructing the air hose or a seal member of the tool and in the latter case, there poses a problem that an inherent function cannot be achieved. In order to prevent the problems, air hoses without the interchangeability are respectively used by constituting the modes of connecting the air hose to the high pressure air take out port and the low pressure air take out port by respectively exclusive shapes, or constituting structures of portions of connecting the plug members or the like of the air hoses by inverse screw structures. Such a well-known technology is disclosed in, for example, JP-A-2003-161302.
On the other hand, as shown by JP-A-2004-230553, there is well known a technology of including a pressure reducing valve at a handle housing portion of the air tool of a low pressure specification and operating the air tool by reducing a pressure of high pressure air supplied from a high pressure air compressor to a pressure of compressed air at a low pressure region by the pressure reducing valve of the air tool per se. According to the technology, the above-described low pressure air take out port from the high pressure compressor is dispensed with and also the modes of connecting the air hoses can be unified to one mode exclusive for the high pressure air take out port. Thereby, a way of use of the high pressure air compressor and the connecting air hose at an operation site is promoted, also the installation cost of the air compressor can be reduced to cost of one piece of the high pressure air compressor and the above-described problems of the related art can be resolved.